---

Background and Objective: Stem cells are a suitable treatment method for improvement of central nervous system diseases. Neuron regeneration is occure in damaged region using stem cell transplantation. This study was done to determine the effect of bone marrow mesenchymal stem cells on memory and neuronal cells graft number in the trimethyltin chloride damaged hippocampus. Methods: In this experimental study, 28 wistar male rats were allocated into four groups including control, model, Vehicle and treatment groups. Animals were received 8 mg/kg/bw of neurotoxin trimethyltin chloride by the intraperitoneal injection for causing damaged in hippocampus. One week after intraperitoneal injection of trimethyltin chloride, stem cells was injected by stereotaxy method. Six weeks after stem cells injection, the spatial memory was assessed by Morris water maze and histological studies were done by Nissl staining and normal cells count by Olysia bio report software. Results: After bone marrow mesenchymal stem cells graft, the number of normal cells were more in the treatment group (74±15.190) in compared to the Vehicle (44.67±12.971) and Model (48.56±18.105) groups (P<0.05). Also in Morris water maze test, the treatment group (387.35±189.18), (31.30±13.67) spent shorter distance and escape latency to reach the hidden platform, but this reduced non significantly in compared to Vehicle (438.18±192.56), (40.14±14.89) and model (407.98±225.44), (37.68±17.15) groups. The model and Vehicle groups spent longer distance to reach the hidden platform in comparision with the control (275.45±165.10) group (P<0.05). Also the traveled distance in target quarter had significant increased in the treatment groups (799.80±125.91) in compared to model (588.51±136.94) and Vehicle (546.48±86.47) groups (P<0.05). Conclusion: Using the bone marrow mesenchymal stem cells leads to reduce hippocampal lesions and increase the number of pyramidal neurons and improving memory in damaged hippocampus in animal model.

---

Background and Objective: Adult neurogenesis occurs in most mammalian species in two main areas of brain: 1- subventricular zone 2- the dentate gyrus of the hippocampus. Many factors such as 17-B estradiol affect neurogenesis in the hippocampus. The aim of this study was to investigate the effect of exogenous 17-B estradiol on neurogenesis and astrocyte functions in the ovariectomized mice.
Methods: In this experimental study; NMRI mice were allocated into five experimental groups including Sham, Control, Treatment with single dose of 17-B estradiol two weeks after ovariectomy (OVX) and were sacrificed 24 hours later, Treatment with single dose of 17-B estradiol two weeks after Ovx and were sacrificed 48 hours later and   Treatment with single dose of Seasame Oil 2 weeks after OVX and were sacrificed after 24 hours. Animals were transcardially perfused with paraformaldehyde. Brains were removed and its sections for cresyl fast violet staining and GFAP immunohistochemistry were prepared. Cells were counted and investigated.
Results: Neuronal density and Proliferation of hippocampal progenitor cells in the CA1 region of 17-B estradiol treated mice significantly increased up to 24 hours (P<0.05). Density of glia and particularly astrocytes in different regions of the hippocampus significantly reduced after treatment with 17-B estradiol (P<0.05).
Conclusion: Density of hippocampal CA1 neurons are influenced by 17-B estradiol. Also, density and morphology of glia cells, especially astrocytes in different regions of the hippocampus are affected by 17-B estradiol.

---

Background and Objective: Multiple Sclerosis (MS) is a neurologic necrotic and chronic illness that causes by demyelination in CNS. One of the common clinical symptoms in MS is cognitive disorders. The most common cognitive defects in patients with MS are reduction of memory and information processing rate hippocampus functions in brain are memory and learning. This study was done to determine the function mechanism of memory discover by study on hippocampus. Nowadays tendency of herbal therapy is increased because of drug's side effects. This study's purpose that is from experimental typ effect of compaind extract of Portulaca olerace, Urtica dioica and Boswellia serrata on memory and number of neurons in CA1 area of hippocampus in induced multiple sclerosis rats.
Methods: In this experimental study 30 male adult rats were randomly allocated into control group, sham group (salin injection), (MS + salin) group, (MS + mixture extract, dose of 200 mg/kg), (MS + mixture extract, dose of 400 mg/kg). MS model was induced by intra hippocampal injection a single dose of ethidium bromide (0.01% ethidium bromide sulotion in 0.9% salin) and in 3 microlitre volume with 1 microlitre in minute rate intraperitoneally. Compaind extract of Portulaca olerace, Urtica dioica and Boswellia serrata were injected as the treatment for 21 days. The shuttle box test was used for evaluation of memory. Dissector method was used for neural density in CA1 of hippocampus. Histopathology method was used for evaluation of the alteration of cells.
Results: Neural density in MS induced group was singnificantly reduced in comparison with control and sham groups (P<0.05). Neural density was singnificantly increased in treatment groups in comparison with MS induced group (P<0.05). Histological results showed that induction of MS caused the disrution of neuron cells in compare to controls, but intraperitonal injection of compaind extract cause neurogenesis in tertment groups. Memory in MS induced group was singnificantly reduced in comparison with control and sham groups (P<0.05), but memory was singnificantly increased in treatment groups in comparison with MS induced group (P<0.05).
Conclusion: Compaind extract of Portulaca olerace, Urtica dioica and Boswellia serrata with dosages of 200 and 400 mg/kg/bw due to neurogenesis and amilioration can effective in memory recovery and neural necrosis in MS disease.

---

Background and Objective: Neurogenesis is the process through which neurons are generated from neural stem cells. This process has been shown to occur in special zones of the adult brain including the subventricular zone (SVZ) of the lateral ventricles and the dentate gyrus of the hippocampus. Gonadal steroids affect different steps of neurogenesis, and cell proliferation seems to be increased by estrogens. This study aimed to investigate the neurogenic changes in the SVZ at different phases of the estrous cycle.
Methods: In this experimental study, 26 NMRI mice were used. The mice were identified by vaginal smear and then divided into 4 groups including proestrus (n=5), estrous (n=7), metestrus (n=7) and diestrous (n=7). Different stages of the estrous cycle were determined by staining vaginal smears. Also, the qualitative assessment of cell proliferation in the SVZ was performed by cresyl fast violet staining and glial fibrillary acidic protein (GFAP) immunohistochemistry at different stages of the estrous cycle.
Results: In microscopic sections stained with cresyl violet, it was observed that cell density in the proestrus stage of the estrous cycle was greater than in any other stages of the estrous cycle. A comparison of sections stained with anti-GFAP showed that the density of astrocytes in proestrus was significantly higher than in other groups.
Conclusion: Proestrus stage of the estrous cycle is associated with increased cell proliferation and density of astrocytes in the SVZ of mice. Neurogenesis is correlated to changes in sex hormonal levels at different phases of the estrus cycle.